This invention relates generally to a composition and method for detersifying and/or removing oxide film or scale from a wide variety of metal alloys, and more particularly to a composition and method for such detersification and/or oxide removal which is relatively mild, non-toxic, has safe disposal products, and which will not attack the base metal, but which will be effective in a reasonable amount of time.
There have been many prior art proposals for agents for detersifying metal surfaces, and also, many proposals for agents for removing oxide films and scales. These have taken many forms. Detersive agents generally have a caustic alkaline type base. Oxide removal agents include strong mineral acids, or mixture of such acids such as H.sub.2 SO.sub.4, HCl, HNO.sub.3 /HF, etc. Also, fused alkaline oxidizing salts are commonly used, as well as certain strong aqueous solution of salts with electolysis, such as Na.sub.2 SO.sub.4, etc. All of these have certain applications in which they function satisfactorily and indeed function quite well in many instances. However, they do have certain draw-backs in many situations. For example the caustics for detersive action are harsh, and skin and eye contact must be avoided, and thus great care must be exercised in their use. The toxicity, and other undesirable properties, such as disposal problems of mineral acids, are well known. Fused salts of course are toxic, require energy to maintain the bath fused, and also pose disposal problems. Electrolytic aqueous baths also require energy to operate and also usually are toxic, and have somewhat narrow ranges of use.